172f52ace994d118941140e575139d76fcb06e14  Block requests with a WebPrivacy provided content rule list instead of a network process check

Classified as not security-relevant.
Triage note: Replaces the mayBlockNetworkRequest/isRequestBlockable path with a new TrackingPreventionContentRuleListController + shouldBlockLoad() plumbing and a staging WebPrivacy API (loadDefaultContentRuleListForStore). This is privacy-feature plumbing/refactor, not a memory-safety or logic bug fix.
This commit was flagged by the signal scorer and reviewed by AI (not a human). It is listed only so the triage is auditable; there is no root-cause analysis because this is not a vulnerability fix.

Structural signals: smartptr_member_added (+6.47), bounds_guard (+2.0), null_guard (+2.59), area:Source/WebCore/loader (+2.0), large_churn (-2.0)